This invention relates to sockets which removably accept compact fluorescent bulbs, and in particular, to a socket which will become part of a lighting fixture in which the fluorescent bulb is inserted.
Fluorescent bulbs are well known. They generate less heat than incandescent bulbs, typically have a longer operating life than fluorescent bulbs, and typically are less expensive to operate than incandescent bulbs. Long tube fluorescent bulbs have long been used in office buildings, home basements, etc. More recently, compact fluorescent bulbs have become available for use in desk lamps, table lamps, ceiling fixtures, etc. Such bulbs are typically known as PL bulbs or lamps in the trade. A typical PL bulb is shown, for example, in U.S. Pat. No. 5,758,952.
Currently existing table lamps, ceiling fixtures, etc. include sockets which accept incandescent bulbs. To enable compact fluorescent bulbs to be used with such fixtures, manufactures have provided throw-away fluorescent bulb assemblies. In such assemblies the bulb is fixed in a base which includes the ballast or other electronics to light the bulb. The base includes a threaded end which can be screwed into an incandescent bulb socket. When the bulb bums out, or otherwise breaks, the whole unit, including the ballast is thrown away. Even though the ballast may still be operable, it is thrown away. An example of such a bulb is shown in U.S. Pat. No. 5,086,249. This type of assembly increases the cost to the consumer, because the consumer must buy the ballast with each bulb that is purchased.
Sockets have also been developed which removably receive compact fluorescent bulbs. Such sockets include the ballast for the fluorescent bulbs and overcome the extra cost to the consumer of having to purchase a ballast with each bulb that is bought. These sockets, however, also include a threaded back end so that they may be used to convert fixtures which accept incandescent bulbs to fixtures which accept fluorescent bulbs.
Fixtures (such as table lamps, ceiling fixtures, and even outdoor lighting fixtures) which are currently available are almost exclusively made for use with incandescent bulbs. I know of no sockets for PL type fluorescent bulbs which include a ballast and which can be used instead of an incandescent bulb socket in such fixture.